Impact on Prairie Pothole Region fisheries focus of climate change study

Jul. 28—The potential impact of a changing climate is an issue facing fisheries managers across the country, and a study underway between researchers at UND and South Dakota State University aims to shed light on what might be ahead for recreational fisheries in the Prairie Pothole Region.

The interdisciplinary research project has three key components: Michaela Neal, a graduate student in UND's Geological Engineering Department, is focusing on hydrology and what might happen during prolonged wet and dry cycles; Maddy Siller, a graduate student at South Dakota State University, is looking at the potential impact on fish populations; and Matthew Maldonado, a graduate student in the UND Biology Department, is exploring how changes in lakes and fish populations could alter angler behavior.

Maldonado's adviser is Mark Kaemingk, a UND assistant professor of aquatic ecology with a background in human dimensions research.

"We're all working to kind of answer this question of what's going to happen to our water bodies in the future," Maldonado said. "How is climate change really going to alter what we have in front of us right now? And what are those effects going to be?"

According to Taufique Mahmood, an associate professor of Geology and Geological Engineering at UND and director of the university's North Dakota Center for Water Research, the study developed in response to the changes that have occurred to lakes and wetlands in the Prairie Pothole Region of North and South Dakota in recent decades.

"The northern part of the northern Great Plains has been experiencing a high precipitation amount over the last 30 years," said Mahmood, who is graduate director of the Harold Hamm School of Geology and Geological Engineering at UND and Neal's adviser. "Particularly since 1990, our water areas are increasing."

At the same time, temperatures are fluctuating.

Perhaps the most striking example is Devils Lake, which rose from an elevation of 1,422.6 feet in 1993 to a record of 1,454.3 feet in 2011, according to a fact sheet from the North Dakota Water Commission. In the process, the lake expanded from 44,230 acres to 211,300 acres.

Today, Devils Lake is at an elevation of 1,450.16 feet.

"It was pretty tiny," Mahmood said. "Lake Alice and Lake Irvine didn't exist in 1990, and from 1990 to 1999, the lake grew and Lake Irvine and Lake Alice started to (form). We have larger areas for fish to migrate, we have a larger area for anglers to fish, and we have a lot of migration routes and pathways there."

The hydrology portion of the study will look at 500 to 600 lakes and how they might respond to water and temperature fluctuations. By setting up a hydrological model for Devils Lake, Mahmood says, they can apply local parameters to model other lakes and wetlands in the Prairie Pothole Region of North and South Dakota.

"We've been using a combination of equations and past field data, including streamflow and climate conditions, to digitally recreate how the Devils Lake Basin has changed in the recent past," Neal said. "So we're trying to go back in time, hour by hour, day by day, over 20 whole years to see how this is working, how has Devils Lake changed its volume over time?

"And then, by understanding that recent past, by extension we can better understand and predict the future. Because now, we intricately know how that lake works."

If the model works for Devils Lake, in other words, it should work for other lakes where less data is available.

"Devils Lake is an ideal laboratory to test anything, the way it kind of responded to a lot of climatic shift," Mahmood said. "So, I think we are confident that if our model is working now in the Devils Lake area — Michaela has some great results — we are going to replicate that into the eastern and the southern North Dakota region and also northern South Dakota, as well."

The expectation, Neal says, is that the "seesawing effect" of wet and dry climates will get stronger and more pronounced.

"At times, we will see such an outpouring of floodwater that the landscape is going to be a saturated sponge and just keep filling and spilling from one pothole to the next all the way downstream," she said. "Those lakes will keep growing far beyond what we've seen in the past.

"And then, at other times, just as we have these brand-new lakes that are emerging, all these new fishing spots will transition into these times where things are drier and will plunge into these droughts unlike anything we've seen before."

A study by the U.S. Geological Survey predicts the current wet cycle will continue until about 2040, Mahmood says, after which dry spells could become more prevalent.

"We have all these things to consider with how much water, and how that changes over time, and then how that's impacting angler access," Neal said. "We have all these different things to consider when we're looking at water, climate, environment, and then humans within that."

Maddy Siller, the SDSU graduate student looking at how fish species might respond to climate change, is using long-term weather, water level and fisheries data from state agencies to predict what fish species will do best in a particular lake, given the changes that might occur.

"One of the things we're kind of looking at is, with the climate changing, the air is able to hold more water, meaning that we have these increased long droughts, but when we do have rain, it's a lot more," Siller said. "And so we're trying to figure out if those changes in precipitation events are going to result in lakes overall being smaller, potentially impacting which fish are going to be able to be there, or if those occasional flood events are going to be increasing the size of the water bodies and which fish can live there."

Walleyes, for example, are a cold-water species, while largemouth bass do well in warmer water.

"We haven't been able to find very many other studies that have looked at these similar aspects or anything, which has been interesting," Siller said. "There's definitely a decent margin of error, which we're trying to be aware of and take into account for making these predictions."

Scott Gangl, fisheries management section leader for the North Dakota Game and Fish Department in Bismarck, is the department's contact for the study, along with John Lott, aquatic section chief for South Dakota Game, Fish and Parks.

Game and Fish, Gangl says, doesn't spend as much time looking at climate change as states such as Minnesota and Wisconsin, where lakes are more static. In North Dakota, by comparison, the number of fishing lakes has grown from about 250 in the 1990s to nearly 450 today.

"Here in North Dakota, our waters are so variable that we're kind of more at the mercy of wet cycles and dry cycles," Gangl said. "We've been in a very extended wet cycle that's actually produced a lot of really good fishing because we have so many new lakes now."

That being said, being able to predict how those new lakes will respond in the future could help the department better allocate resources, such as where to build permanent boat ramps or maintain aggressive stocking programs, Gangl said.

"This research, if it provides some insight into some of those things, like where do we stick our resources, that can help guide how we develop these new lakes into the future," he said.

Maldonado, the UND student whose focus is human dimensions, is exploring how climate-related changes to water body size impact angler use, the economic value of a fishery and the decisions managers ultimately make in managing a fishery.

He'll give a presentation on his research in August during the annual meeting of the American Fisheries Society in Grand Rapids, Michigan.

"Most people when they do research, their main stakeholders are the anglers themselves, but angler managers are just as important for a fishery," Maldonado said. "And so, trying to figure out and hone that decision-making process as we get further and further into climate change is going to be incredibly important to keeping anglers happy."

Understanding how angler behavior changed from the beginning of the wet cycle in the early '90s until now could provide insights into how anglers react to climate-induced water body changes in years to come, he says.

"One of the things we're going to be looking at is trying to identify lakes that are more at risk of water body size changes," Maldonado said. "And of those lakes, are there any that are susceptible to angler effort changes? We're looking for some of these hotspots of areas that we think could see alterations in the amount of money generated."

The three graduate students will use the research in developing and writing their master's degree theses. Interdisciplinary research, which connects people across fields, is becoming "increasingly necessary," said Neal, the UND graduate student focusing on the hydrology aspect of the project.

"We're coming to find we need more and more connections across fields to find solutions for our increasingly interconnected world," Neal said. "And so interdisciplinary research like this — where we're looking at hydrology, water, we're looking at angler behavior, we're looking at fish communities — that provides a more comprehensive picture so that we can find a path forward and know what to expect going into the future."